Buggy code:
public class InstanceExpression implements IntInstanceExpression , Serializable { private static final long serialVersionUID = - 6296982198124042304L ; private static HlclFactory hlclFactory = new HlclFactory ( ) ; private SemanticExpression volatileSemanticExpression ; private SemanticExpression customSemanticExpression ; private InstElement volatileLefInstElement ; private InstElement volatileRightInstElement ; private InstanceExpression leftInstanceExpression ; private InstanceExpression rightInstanceExpression ; private List < ExpressionSubAction > SemExprSubActions ; private String leftValue ; private String rightValue ; private String lastLeft = null ; private String lastRight = null ; private boolean customExpression ; private String semanticExpressionId ; private String rightInstElementId ; private String leftInstElementId ; public String getLastLeft ( ) { } public void setLastLeft ( String lastLeft ) { } public String getLastRight ( ) { } public void setLastRight ( String lastRight ) { } public InstanceExpression ( ) { } public void loadVolatileElements ( Map < String , InstElement > instVertices ) { } public InstanceExpression ( boolean customExpression , String id , boolean first ) { } public InstanceExpression ( boolean customExpression , SemanticExpression semanticExpression ) { } public InstanceExpression ( SemanticExpression semanticExpression , InstElement left , InstElement right ) { } public InstanceExpression ( SemanticExpression semanticExpression , InstElement vertex , boolean replaceTarget , InstanceExpression instanceExpression ) { } public InstanceExpression ( SemanticExpression semanticExpression , InstanceExpression leftInstanceExpression , InstanceExpression rightInstanceExpression ) { } public InstanceExpression ( SemanticExpression semanticExpression , InstElement vertex ) { } public Expression createSGSExpression ( String element ) { } public Expression createExpression ( ) { } private Identifier getIdentifier ( ExpressionVertexType expressionVertexType ) { } private void updateDomain ( AbstractAttribute attribute , InstElement instVertex , Identifier identifier ) { if ( attribute . getName ( ) . equals ( VAR_VARIABLECONFIGVALUE ) ) { String configdomain = ( ( String ) ( volatileLefInstElement . getInstAttribute ( VAR_VARIABLECONFIGDOMAIN ) . getValue ( ) ) ) ; <START_BUG> if ( configdomain != null ) <END_BUG> identifier . setDomain ( DomainParser . parseDomain ( configdomain ) ) ; } if ( attribute . getName ( ) . equals ( VAR_VALUE ) ) { String type = ( ( String ) ( instVertex . getInstAttribute ( VAR_VARIABLETYPE ) . getValue ( ) ) ) ; if ( type . equals ( "Integer" ) ) { String domain = ( ( String ) ( instVertex . getInstAttribute ( VAR_VARIABLEDOMAIN ) . getValue ( ) ) ) ; identifier . setDomain ( DomainParser . parseDomain ( domain ) ) ; } else if ( type . equals ( "Enumeration" ) ) { Object object = instVertex . getInstAttribute ( "enumerationType" ) . getValueObject ( ) ; String domain = "" ; if ( object != null ) { @ SuppressWarnings ( "unchecked" ) Collection < InstAttribute > values = ( ( Collection < InstAttribute > ) ( ( ( InstAttribute ) ( ( ( com . variamos . perspsupport . instancesupport . InstEnumeration ) ( object ) ) . getInstAttribute ( MetaEnumeration . VAR_METAENUMVALUE ) ) ) . getValue ( ) ) ) ; for ( InstAttribute value : values ) { String [ ] split = ( ( String ) ( value . getValue ( ) ) ) . split ( "-" ) ; domain += ( split [ 0 ] ) + "," ; } } domain = domain . substring ( 0 , ( ( domain . length ( ) ) - 1 ) ) ; identifier . setDomain ( DomainParser . parseDomain ( domain ) ) ; } } else if ( attribute . getType ( ) . equals ( "Integer" ) ) { if ( ( attribute . getDomain ( ) ) != null ) identifier . setDomain ( attribute . getDomain ( ) ) ; else identifier . setDomain ( new RangeDomain ( 0 , 4 ) ) ; } } private List < Expression > expressionTerms ( ) { } private int getVariableIntValue ( ExpressionVertexType expressionVertexType ) { } public InstElement getLeftElement ( ) { } public void setLeftElement ( InstElement leftElement ) { } public InstElement getRightElement ( ) { } public void setRightElement ( InstElement rightElement ) { } public InstanceExpression getLeftInstanceExpression ( ) { } public void setLeftInstanceExpression ( InstanceExpression leftSubExpression ) { } public InstanceExpression getRightInstanceExpression ( ) { } public void setRightInstanceExpression ( InstanceExpression rightSubExpression ) { } public void setLeftInstanceExpression ( ExpressionVertexType type , SemanticExpressionType semanticExpressionType , String id ) { } public void setLeftElement ( InstElement instElement , String attribute ) { } public void setRightInstanceExpression ( ExpressionVertexType type , SemanticExpressionType semanticExpressionType , String id ) { } public void setRightElement ( InstElement instElement , String attribute ) { } public int getLeftNumber ( ) { } public int getRightNumber ( ) { } public void setLeftNumber ( int number ) { } public void setRightNumber ( int number ) { } public void setSemanticExpressionType ( SemanticExpressionType semanticExpressionType ) { } public int getLeftValidExpressions ( ) { } public int getRightValidExpressions ( ) { } public int getResultExpressions ( ) { } public SemanticExpression getSemanticExpression ( ) { } public void setSemanticExpression ( SemanticExpression semanticExpression ) { } public SemanticExpression getCustomSemanticExpression ( ) { } public void setCustomSemanticExpression ( SemanticExpression customSemanticExpression ) { } public boolean isCustomExpression ( ) { } public void setCustomExpression ( boolean customExpression ) { } public String getSemanticExpressionId ( ) { } public void setSemanticExpressionId ( String semanticExpressionId ) { } public String getLeftAttributeName ( ) { } public String getRightAttributeName ( ) { } public void setLeftAttributeName ( String attribute ) { } public void setRightAttributeName ( String attribute ) { } public String getOperation ( ) { } public ExpressionVertexType getLeftExpressionType ( ) { } public ExpressionVertexType getRightExpressionType ( ) { } public void setLeftExpressionType ( ExpressionVertexType expressionVertexType ) { } public void setRightExpressionType ( ExpressionVertexType expressionVertexType ) { } public String getSideElementIdentifier ( ExpressionVertexType expressionVertexType ) { } public String getRightInstElementId ( ) { } public void setRightInstElementId ( String rightElementId ) { } public String getLeftInstElementId ( ) { }

Fix:
if ( ( configdomain != null ) && ( ! ( configdomain . equals ( "" ) ) ) )